Engine/Transmission (1994 - 1998) i may of figured out the cycling thermostat temp gauge thing

[WDixon27]

i need some more testing as i only had the 20 mile drive home that got interrupted by a lovely traffic jam that screwed up the last 10 miles, but even then it didn't cycle it got up to 200 slowly and stayed there at 70 mph, and when i was idling in traffic it dropped a couple needle widths below 200 and pretty much stayed there till i got back up to speed at which point it returned to 200. i recently installed a new t-stat (truck didn't have one when i bought it) from the dodge store that came in a cummins box with a august 05 date on the label, i was annoyed to discover it gave me the 1/3 to 2/3s and back swing of the temp gauge that seems to be somewhat common here, on the bmws and volvos i work on everyday this would be death, this evening i pulled the t-stat and looked at the design of it and the housing and decided the t-stat was too isolated from the flow of coolant through the bypass and overreacts, i drilled a couple small holes in the inner part of the t-stat so it would get some flow so it wouldn't get shocked by the temp so much and slam open and closed, i've been drilling holes in thermostats for years to help in bleeding the systems of contrary/complex air pocket prone euro cars, i guess the little hose that bypasses the t-stat to allow the system to burp works too well

 

[Canadian Cummins]

Hole location?

Hey this sound logical.

I would like to do this to the T'stat that I just bought from Cummins, P/N 3928499.

Where exactly did you drill and what size drill did you use.

I don't want to drill into the expansion chamber & screw up a new T'start

Thanks

CC

 

[WDixon27]

it changes for the style of thermostat

i am not sure if all cummins t-stats are the same style, mine looks like this one

http://cgi.ebay.com/ebaymotors/Dodg...33603QQitemZ8011383720QQrdZ1QQsspagenameZWDVW

and i drilled about a 2mm hole in the shroud that the element is inside of, of corse this means you must not go too far or you will punch a hole in the element but theres a few mm of clearance, i put it there so heat could directly access the element as i've never dealt with this style of t-stat i am not sure of it's quirks yet, X marks the spot

#ad


this is the style i am use to dealing with and a hole in the inner plate (part that opens and closes) gets the job done, http://cgi.ebay.com/ebaymotors/1347...ewItemQQcategoryZ46096QQitemZ7975437622QQrdZ1

make sure you clean out all of the debris from drilling

 

[firemanmarc]

I don't know, but I put a thermostat I had for one of my farm tractors that has a 5. 9L and my temp gauge don't move flucuate at all when my fan is actually on the truck, I take my fan off this time of year so it will warm up quicker... . Marc

 

[WDixon27]

I don't know, but I put a thermostat I had for one of my farm tractors that has a 5. 9L and my temp gauge don't move flucuate at all when my fan is actually on the truck, I take my fan off this time of year so it will warm up quicker... . Marc

from what i've read not all of them do it, mine behaved all day so i guess it's a success at least for me however i may get a cooler unit as i am not wild with 200 but for now it'll do

 

[TRAMPLINEMAN]

I don't know, but I put a thermostat I had for one of my farm tractors that has a 5. 9L and my temp gauge don't move flucuate at all when my fan is actually on the truck, I take my fan off this time of year so it will warm up quicker... . Marc

Do you happen to know the part number of the one from the tractor?

 

[firemanmarc]

I will have to dig it up, I am pretty sure I have it... Marc